Model-based Speech Enhancement for Intelligibility Improvement in Binaural Hearing Aids

Speech intelligibility is often severely degraded among hearing impaired individuals in situations such as the cocktail party scenario. The performance of the current hearing aid technology has been observed to be limited in these scenarios. In this paper, we propose a binaural speech enhancement framework that takes into consideration the speech production model. The enhancement framework proposed here is based on the Kalman filter that allows us to take the speech production dynamics into account during the enhancement process. The usage of a Kalman filter requires the estimation of clean speech and noise short term predictor (STP) parameters, and the clean speech pitch parameters. In this work, a binaural codebook-based method is proposed for estimating the STP parameters, and a directional pitch estimator based on the harmonic model and maximum likelihood principle is used to estimate the pitch parameters. The proposed method for estimating the STP and pitch parameters jointly uses the information from left and right ears, leading to a more robust estimation of the filter parameters. Objective measures such as PESQ and STOI have been used to evaluate the enhancement framework in different acoustic scenarios representative of the cocktail party scenario. We have also conducted subjective listening tests on a set of nine normal hearing subjects, to evaluate the performance in terms of intelligibility and quality improvement. The listening tests show that the proposed algorithm, even with access to only a single channel noisy observation, significantly improves the overall speech quality, and the speech intelligibility by up to 15%.Comment: after revisio

GIS-baseret, objekt-orienteret modellering af kollektive transportterminaler

Baggrunden for artiklen er konstruktionen af en udvidelse til Transport Object Platform (TOP), der er en GIS-baseret objektorienteret Platform til at beskrive rutebaseret trafik (Grevy. m.fl., 2001). Konstruktionen af udvidelsen – herefter benævnt terminalmodellen – har som hovedformål at beskrive passagerers rutevalg internt i transportterminaler. Arbejdet blev startet i K. F. Hansen (2002), og er fortsat siden i forbindelse med et forskningsprojekt ved Centre for Trafik og Transport (CTT), DTU. Endvidere har arbejdet haft to væsentlige delmål. Dels at sikre at konceptet for terminalmodellen er tilpasset den overordnede terminologi, der ligger til grund for TOP. Og dels at sikre at konstruktionen af terminalmodellen kan sammenkædes med eksisterende terminalbeskrivelser på andre aggregeringsniveauer ved hjælp af converters til at oversætte data mellem disse. Fordelen ved en objektorienteret datamodel er bl.a. muligheden for fleksibelt at arbejde på forskellige aggregeringsniveauer. I forbindelse med trafikmodeller, f.eks. fjernoplande, centrale regioner, samt detailmodellering af bestemte terminaler. Det kan være inden for samme model, f.eks. modellering af passagertunnellen på Nørreport Station eller de forskellige forslag til udvidelse af Københavns Hovedbanegård, hvor passagerudvekslingen sker mellem såvel bus og S-tog (Københavnsområdet), som regional og fjerntog (Fjernoplande), men hvor den detaljerede udformning af terminalen også er interessant. Men det kan også være i forbindelse med interaktion mellem modeller. F.eks. hvor en model for København interagerer med en model for Øresundsregionen, der måske igen interagerer med en model for Skandinavien. Et sådan hierarki er relevant for persontrafik, men måske i særlig grad for godstransport, hvor andelen af lange ture er større. I forbindelse med arbejdet terminalmodellen har taget udgangspunkt i persontrafik, men kan lige såvel dække liniebåret godstransport, såsom tog, skibsfart og rutebåret lastbiltrafik. Et arbejde med udvikling af en sådan model pågår i forbindelse med Center for forskning i logistik og godstransport (CLG), der ledes af CTT

Widespread erosion on high plateaus during recent glaciations in Scandinavia

Glaciers create some of Earth’s steepest topography; yet, many areas that were repeatedly overridden by ice sheets in the last few million years include extensive plateaus. The distinct geomorphic contrast between plateaus and the glacial troughs that dissect them has sustained two long-held hypotheses: first, that ice sheets perform insignificant erosion beyond glacial troughs, and, second, that the plateaus represent ancient pre-glacial landforms bearing information of tectonic and geomorphic history prior to Pliocene–Pleistocene global cooling (~3.5 Myr ago). Here we show that the Fennoscandian ice sheets drove widespread erosion across plateaus far beyond glacial troughs. We apply inverse modelling to 118 new cosmogenic 10Be and 26Al measurements to quantify ice sheet erosion on the plateaus fringing the Sognefjorden glacial trough in western Norway. Our findings demonstrate substantial modification of the pre-glacial landscape during the Quaternary, and that glacial erosion of plateaus is important when estimating the global sediment flux to the oceans

Impaired Reproductive Development in Sons of Women Occupationally Exposed to Pesticides during Pregnancy

OBJECTIVES: The aim of this prospective study was to investigate whether occupational pesticide exposure during pregnancy causes adverse effects on the reproductive development in the male infants. DESIGN AND MEASUREMENTS: Pregnant women employed in greenhouses in Denmark were consecutively recruited, and 113 mother–son pairs were included. The mothers were categorized as occupationally exposed (91 sons) or unexposed (22 sons) to pesticides during pregnancy. Testicular position and volume, penile length, and position of urethral opening were determined at 3 months of age using standardized techniques. Concentrations of reproductive hormones in serum from the boys were analyzed. RESULTS: The prevalence of cryptorchidism at 3 months of age was 6.2 % [95 % confidence interval (CI), 3.0–12.4]. This prevalence was considerably higher than among Danish boys born in the Copenhagen area (1.9%; 95 % CI, 1.2–3.0) examined by the same procedure. Boys of pesticideexposed mothers showed decreased penile length, testicular volume, serum concentrations of testosterone, and inhibin B. Serum concentrations of sex hormone-binding globulin, follicle-stimulating hormone, and the luteinizing hormone:testosterone ratio were increased compared with boys of nonexposed mothers. For individual parameters, only the decreased penile length was statisticall

Freshening increases the susceptibility to heat stress in intertidal mussels (Mytilus edulis) from the Arctic.

Funder: William Demant FondenFunder: DANCEAFunder: Familien Hede Nielsens Fond; Id: http://dx.doi.org/10.13039/501100007438Funder: Selskabet for Arktisk Forskning og TeknologiFunder: Aage V. Jensens Fond; Id: http://dx.doi.org/10.13039/501100002721Temperatures in the Arctic are increasing at a faster pace than at lower latitudes resulting in range expansion of boreal species. In Greenland, the warming also drives accelerating melt of the Greenland Ice Sheet resulting in more meltwater entering Greenland fjords in summer. Our aim was to determine if increasing summer temperatures combined with lower salinity can induce the expression of stress-related proteins, for example, heat shock protein, in boreal intertidal mussels in Greenland, and whether low salinity reduces the upper thermal limit at which mortality occurs. We conducted a mortality experiment, using 12 different combinations of salinity and air temperature treatments during a simulated tidal regime, and quantified the change in mRNA levels of five stress-related genes (hsp24, hsp70, hsp90, sod and p38) in surviving mussels to discern the level of sublethal stress. Heat-induced mortality occurred in mussels exposed to an air temperature of 30°C and mortality was higher in treatments with lowered salinity (5 and 15‰), which confirms that low habitat salinity decreases the upper thermal limit of Mytilus edulis. The gene expression analysis supported the mortality results, with the highest gene expression found at combinations of high temperature and low salinity. Combined with seasonal measurements of intertidal temperatures in Greenland, we suggest heat stress occurs in low salinity intertidal area, and that further lowered salinity in coastal water due to increased run-off can make intertidal bivalves more susceptible to summer heat stress. This study thus provides an example of how different impacts of climate warming can work synergistically to stress marine organisms

SvSXP:a <em>Strongylus vulgaris</em> antigen with potential for prepatent diagnosis

BACKGROUND: Strongyle parasites are ubiquitous in grazing horses. Strongylus vulgaris, the most pathogenic of the large strongyles, is known for its extensive migration in the mesenteric arterial system. The lifecycle of S. vulgaris is characterised by a long prepatent period where the migrating larvae are virtually undetectable as there currently is no test available for diagnosing prepatent S. vulgaris infection. Presence of S. vulgaris larvae in the arterial system causes endarteritis and thrombosis with a risk of non-strangulating intestinal infarctions. Emergence of anthelmintic resistance among cyathostomins has led to recommendations of reduced treatment intensity by targeting horses that exceed a predetermined strongyle faecal egg count threshold. One study suggests an apparent increase in prevalence of S. vulgaris on farms where reduced anthelmintic treatment intensity has been implemented. These issues highlight the need for an accurate and reliable assay for diagnosing prepatent S. vulgaris infection. METHODS: Immunoscreening of a larval S. vulgaris cDNA library using hyperimmune serum raised against S. vulgaris excretory/secretory antigens was performed to identify potential diagnostic antigens. Immunoreactive clones were sequenced, one potential antigen was characterised, expressed as a recombinant protein, initially evaluated by western blot (WB) analysis, the diagnostic potential of the IgG subclasses was evaluated by ELISA, and the diagnostic accuracy evaluated using serum from 102 horses with known S. vulgaris infection status. RESULTS: The clone expressing the potential antigen encoded a S. vulgaris SXP/RAL2 homologue. The recombinant protein, rSvSXP, was shown to be a potential diagnostic antigen by WB analysis, and a target of serum IgGa, IgG(T) and total IgG in naturally infected horses, with IgG(T) antibodies being the most reliable indicator of S. vulgaris infection in horses. Evaluation of diagnostic accuracy of the ELISA resulted in a sensitivity of 73.3%, a specificity of 81.0%, a diagnostic odds ratio of 11.69; a positive likelihood ratio (LR) of 3.85 and a negative LR was 0.33. The area under the ROC curve was 0.820. CONCLUSION: IgG(T) antibodies to recombinant SvSXP show potential for use as an antigen for prepatent diagnosis of migrating stages of S. vulgaris with moderate to good diagnostic accuracy